Proper care and maintenance of a lawn or turf area requires periodic application of fertilizers, herbicides, insecticides, and other chemicals depending on the condition of the lawn to be treated. Since the task of proper lawn maintenance can be time consuming, difficult and tiring, particularly to the individual homeowner, professional lawn care services have become increasingly popular. Traditionally, such services apply fertilizers and herbicides to turf areas, usually at regular intervals of four or five times per growing season. The primary method of application has been to mix the prescribed herbicides with a liquid fertilizer solution in a large truck mounted tank from which the mixture is pumped through a hose to a nozzle or hand spray wand and applied to the lawn. At best this method of application leaves much to be desired. Properly trained operators must master the technique of hand spraying the chemicals uniformly in order to insure even turf growth and color, proper control of weeds, and to avoid chemical damage to the turf or adjacent ornamentals. Such method is highly susceptible to wind conditions since with the liquid leaving the hand gun at waist height or higher even a slight wind can cause the sprayed materials to drift from a targeted area into unwanted places.
Because of the difficulty of the hand spraying application, dry fertilizer products have been resorted to. By using a good quality, properly calibrated spreader it is quite easy to uniformly spread the dry fertilizer products. In order to alleviate the cost and labor of applying liquid herbicides independently of the dry products, combination dry herbicide and granular fertilizer products have been introduced. However, the cost and treatment effectiveness of the dry herbicides has seriously detracted from popularity of such products despite the capability of uniform product distribution and lessening wind effect on the application. As a result the lawn service industry has more recently returned to the original liquid application methods. However, the support equipment for this system, requiring multiple storage tanks, elaborate pumping systems, high volume water supply and increasing costs of liquid application truck equipment has become a heavy cost burden to the lawn service operator, as well as the purchaser of the services.
In recognition of the foregoing indicated problems and drawbacks of traditional equipment and materials presently in use in the lawn service industry, there is a need for a cost efficient application system which can apply both dry fertilizer and liquid weed controls simultaneously or independently at the operator's command while carrying out such functions as the equipment traverses the turf area to be serviced. Such equipment must also be of a size capable of being readily maneuvered around obstacles or through narrow passageways, such as gates or entrance-ways, encountered by the operator during the application procedures.
The present invention is directed to the provision of improved equipment for applying wet and dry lawn treatment materials and to a method of application which alleviates many of the aforenoted problems and application difficulties encountered in lawn or turf maintenance problems.
Combination machines for applying wet and dry treatment materials such as dry fertilizers and liquid herbicides, etc., have been developed heretofore, but have experienced limited success. Typifying such prior developments, for example, is the wet/dry spreader taught in U.S. Pat. No. 4,352,463 issued to Baker on Oct. 5, 1982. In accordance with that patent a power driven combination wet and dry lawn treatment spreader is disclosed wherein dry fertilizer materials are stored in a hopper and fed by gravity to a spinning impeller which distributes or broadcasts the granulated materials in a fan-like pattern. Liquid treatment materials are sprayed in a similar pattern. The wet materials are supplied from a remote tank truck via a hose connected to the spreader. Provision of the remote supply truck tank and pump and the interconnecting hose makes manipulation of the spreader cumbersome and of limited maneuverability inasmuch as the heavy hose must be dragged over the terrain to be treated.
A later development is found in U.S. Pat. No. 4,483,486 issued to Magda on Nov. 20, 1984, in which a self-contained combination wet/dry spreader is taught. The dry granulated materials are broadcast by an spinning impeller in response to manual driving of the spreader; the spreader carrying tanks of liquid material which are pumped to a spray nozzle by means of a pump means driven in response to movement of the spreader. In this particular apparatus the spray pattern is laterally isolated from the dry material pattern of distribution, thereby seriously impairing uniformity of distributing both liquid and dry products simultaneously.